Calculating Tire Revolutions and Angular Speed in a Braking Car

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Homework Help Overview

The problem involves a car that is decelerating due to braking, with specific parameters given for initial speed and acceleration. The questions focus on calculating the number of tire revolutions before the car stops and determining the angular speed of the wheels at a certain distance.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the use of kinematic equations to determine time and distance during deceleration. There is uncertainty about calculating the number of revolutions and the angular speed of the tires. Questions arise regarding the average speed of the car and the relationship between distance traveled and tire circumference.

Discussion Status

Some participants have provided hints regarding the average speed and tire circumference, suggesting a collaborative exploration of the problem. There is an ongoing dialogue about the calculations and assumptions involved, but no consensus has been reached on the correct approach or solution.

Contextual Notes

Participants are working within the constraints of a homework assignment, which may limit the information they can use or the methods they can apply. There is an emphasis on ensuring calculations are accurate and relevant to the problem context.

balling12
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Homework Statement


A car initially traveling at 25.9 m/s undergoes a constant negative acceleration of magnitude 2.10 m/s2 after its brakes are applied.
(a) How many revolutions does each tire make before the car comes to a stop, assuming the car does not skid and the tires have radii of 0.330 m? ... revs
(b) What is the angular speed of the wheels when the car has traveled half the total distance? .. rad/s



Homework Equations





The Attempt at a Solution


I used the kinematic equation to find the time it takes to come to a stop: 12.3 secs and the distance traveled: 305.67 m. I am unsure how to find the number of revolutions the tires make. However i worked out part B using the equation: W final^2=W initial^2+ 2(alpha)(Change in theta) and got the answer 19.1 rads but it is wrong.
 
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balling12 said:
I used the kinematic equation to find the time it takes to come to a stop: 12.3 secs and the distance traveled: 305.67 m.
Redo that last calculation. Hint: What's the average speed of the car as it comes to rest?
I am unsure how to find the number of revolutions the tires make.
Hint: What's the circumference of the tires?
 
Doc Al said:
Redo that last calculation. Hint: What's the average speed of the car as it comes to rest?
im not sure?

Hint: What's the circumference of the tires?
Circumference is pie x diameter right?
 
balling12 said:
Circumference is pie x diameter right?
Yes.
 

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